EP3630935B1 - Method for crossflow during membrane filtration of beer - Google Patents

Description

The invention relates to a filter device and a filtration method with at least one module package according to the preamble of patent claims 1 and 10.

Membrane filtration (microfiltration) of beer for beer clarification has been an increasingly accepted technology in recent years. The crossflow method is preferably used here, in which the unfiltrate, here the unfiltered beer, is guided along a membrane through the crossflow filter module 2, as shown, for example 7 emerges. During filtration, retained components (e.g. yeast or a mixture of different proteins and polysaccharides, etc.) are concentrated on the unfiltrate side (retentate side). If the unfiltrate concentration remains the same and the amount of filtrate removed remains the same, the concentration increases as a function of the retentate circulation time. Depending on the process, the retained highly concentrated components can either remain completely in the circuit until the end of the filtrate or they are partially drawn off into additional concentration tanks and dosed later in a targeted manner, e.g 8 emerges. The concentration tank can be the unfiltrate buffer tank, for example. So teaches DE10164555 a crossflow microfiltration system with at least two crossflow filter modules, which is connected to an unfiltrate/retentate circuit with unfiltrate inlet lines and retentate outlet lines, to a filtration line with filtrate outlet lines and first filtrate shut-off valves and to a filtrate return line with filtrate inlet lines and second filtrate shut-off valves.

All of these methods have in common that they concentrate the unfiltrate/retentate over the course of the filtration, so that the membranes of the modules are covered with a cover layer. In addition, some components are adsorbed in the pores of the membrane, which leads to fouling of the membrane on the surface and inside. Due to the contamination of the membrane, the transmembrane pressure increases, whereby there is a limit at which the filtration has to be stopped and the concentrate has to be disposed of (for example in a used yeast tank). Afterwards there is the possibility, for example, to start the filtration again, backwash and then continue to filter or to carry out a complete cleaning/CIP cleaning (cleaning in place).

This depends on the contamination level of the membrane and the basic cleaning strategy. Therefore, as a rule, an intermediate cleaning step or a complete cleaning/CIP cleaning is carried out when a predetermined mean transmembrane pressure (TMD) is reached/exceeded. The cleaning is then usually carried out with various cleaning media such as water, alkalis, acids and additives. It is desirable to extend the service life of the modules, ie to increase the cleaning intervals and to carry out the filtration as efficiently as possible, since production losses as a result of cleaning are associated with considerable costs.

Proceeding from this, the present invention is based on the object of providing a filter device and a filtration method which in a simple manner extend the service life of the modules and at the same time enable efficient cleaning.

According to the invention, this object is achieved by the features of claims 1 and 10.

According to the present invention, the filter device has at least one module package that includes several, in particular at least three, crossflow modules, each of which has a first unfiltrate connection at a first end and a second unfiltrate connection on the opposite side of the module, as well as at least one filtrate outlet. It is advantageous if the module has two (in the sense of at least two) spaced filtrate outlets, which are arranged in particular at opposite ends or end regions of the module. According to the present invention, a valve arrangement is provided which is designed in such a way that unfiltrate can flow through the individual modules either from the first or from the second unfiltrate connection.

The interconnection according to the invention has significant advantages. It has been shown that the filtration and thus also the contamination is uneven over the running length of the membrane. The same is unfavorable for the filtrate quality and particularly unfavorable for the service life of the membrane. Through the targeted switching of the valve arrangement, the direction of the unfiltrate flow can thus be set or changed with a filter device according to the present invention, such that uniform contamination occurs in the direction of flow across the membrane, or a cleaning effect takes place through targeted switching or pulsing of modules . Since the arrangement according to the invention makes it possible to work in all flow directions in series connection or parallel operation, blocking of the membrane in the respective modules can be effectively delayed and the service life can be increased. The corresponding structure is also advantageous for cleaning purposes, since individual modules can be switched through corresponding valves and piping and the individual modules can be backwashed and/or cleaned in a targeted manner. It is also possible to decouple individual modules from the series connection or to switch a bypass through targeted connection.

Backflushing means that a backflushing medium is fed against the direction of filtration, ie from the filtrate side through the membrane to the non-filtrate side. For example, beer, water, or beer and water can be used as the backwash medium. Backwashing can take place during the actual filtration process.

Cleaning means cleaning with cleaning medium, whereby the cleaning medium can be guided in the direction of filtration, i.e. from the non-filtrate side to the filtrate side, or in the opposite direction to filtration, i.e. from the filtrate side to the non-filtrate side. Cleaning takes place after the actual filtration process. For example, acid (possibly with additives), lye (possibly with additives), other chemical cleaning agents (which have enzymes, for example), or even water can be used as the cleaning medium.

Since it is possible to clean or backwash the modules individually, each module can be cleaned according to its individual needs, i.e. depending on the length, intensity and degree of soiling. In particular, the module that is to be cleaned or backwashed can actually be cleaned or backwashed, specifically individually with the necessary intensity. In the case of modules connected in parallel or in series and cleaned at the same time, this is not clearly guaranteed, since less contaminated membranes always have a higher filtrate flow during filtration and thus a higher flow of cleaning medium than is the case with dirty modules. The consequence of this can be that the heavily soiled membranes are not clean after cleaning, i.e. have not been cleaned sufficiently, which makes it difficult or even prevents the membrane from being loaded evenly again with particles (pollution load) during the next filtration(s).

According to a preferred embodiment, the modules are arranged parallel to one another, with their respective first unfiltrate connection being connected to a first common line section of a unfiltrate line and their respective second unfiltrate connection being connected to a second common line section of the unfiltrate line, with the respective first and second unfiltrate connections valve devices are arranged, which can be switched in such a way that the respective module can be flowed through with unfiltrate from the first or second unfiltrate connection. In this case, the first and second line sections of the unfiltrate line are connected in order to enable the unfiltrate of the modules to circulate in a circuit.

This is possible in particular because a membrane module has two non-filtrate inlets (one above and one below), two non-filtrate outlets (one above and one below) and two filtrate outlets (one above, one below). During operation (filtration and/or cleaning), one unfiltrate inlet, one unfiltrate outlet and one filtrate outlet are preferably always open, the others are closed. With regard to unfiltrate, for example, an inlet and an outlet are open on opposite module sides. Particularly beneficial is also when the filtrate outlet on the side opposite the unfiltrate inlet is open and the filtrate outlet on the unfiltrate inlet side remains closed, so that an optimal, complete flow through the module and its membrane is achieved. Equal opening of unfiltrate inlet and filtrate outlet leads to an uneven, incomplete membrane/membrane module flow and reduces not only the filtrate flow but also the service life of the membrane. When the direction is reversed, the positions of the open and closed valves are reversed. As a result, a flow reversal that can be implemented in a structurally particularly simple manner is achieved. This circuit is suitable both for production with beer (= filtration) and for cleaning.

In general, the invention enables the valve devices of the valve arrangement to be switched in such a way that the modules can be operated in series and in particular the direction in which the unfiltrate can flow through the respective module can be adjusted for each module. A parallel connection is also possible.

If several modules are provided according to the invention, the valve devices can be switched in such a way that when unfiltrate can flow through a module in a first direction and a subsequent module can flow through it in the second direction, which is opposite to the first direction. This can be the immediately following module or a subsequent one. It is also possible for the valve devices to be switched in such a way that at least one module is bypassed, which can be particularly advantageous during backwashing, since residues that are rinsed off do not have to be routed through downstream membranes to discharge the deposits.

By reversing the direction of flow in, for example, a single hollow fiber, the gradient of the pressure drop of the flow through the hollow fiber (several hollow fibers together form a module) is reversed over the length. This also reverses the local transmembrane pressure over the length of the membrane. The effect of this is that the membrane of the module is locally loaded with dirt to varying degrees. A large transmembrane pressure difference at the inlet of a module causes dirt to be pressed more strongly into the pores of the membrane, which makes subsequent cleaning more difficult. A small transmembrane pressure difference at the outlet of the membrane hollow fiber, on the other hand, only causes a small amount of dirt to be transported to the membrane. This also means a lower local flux through the membrane of the module. Is now at certain times, or amounts, or increase in transmembrane pressure per amount, or increase in transmembrane pressure per time If the flow is reversed, the membrane can be loaded evenly with dirt. In addition, the parts of the membrane that are still clean can be fully utilized for positive filtration.

According to a preferred embodiment, the filter arrangement comprises a number of module packages which form a module unit.

The flow can now be reversed in a module package in such a way that the unfiltrate flow direction of the unfiltrate volume flow is reversed as a whole, so that the flow direction is changed in such a way that the individual modules of the module package, which are first flowed through starting from the left, then after the flow reversal be flown through from right to left.

On the other hand, the flow reversal in the individual modules of the module package can be achieved in such a way that the unfiltrate flow direction is maintained, for example from left to right, but the valve position of the module package is changed in such a way that for the unfiltrate inlets become outlets and outlets become inlets and so on the entire module package a flow reversal is achieved in each individual module.

This series connection is only made possible by the connection of unfiltrate inlets and unfiltrate outlets, which is particularly constructive, and which can also experience a flow reversal as a whole or only partially.

For the filtration of beer or cleaning and backwashing of the membrane modules, it is also particularly advantageous if the valve device has control valves or flow controllers, especially in the filtrate discharge line, such that the flow (volume per time) or a value proportional thereto can flow through a module or .Module unit (consisting of 1+n modules, which can be combined on a separate filtrate line) can be adjusted, in particular the flow of all modules in a module package can be set to the same value, which means both uniform production of beer and uniform cleaning or backwashing of all modules of a module package.

It is possible for filtrate to be routed from the at least one filtrate outlet of at least one module for backwashing into the at least one filtrate outlet of at least one other module. According to a preferred embodiment, the respective at least one filtrate outlet of a module opens into a respective filtrate outlet line, with n modules in a module package, in particular the nth filtrate outlet of an nth module of one first module package and the nth filtrate outlet of a second module package lead to a common nth filtrate outlet. (where n is an integer) This means that two modules, one from a first and one from a second module package, are coupled via a common filtrate line. This allows, for example, backwashing of individual modules of a second module package by filtrate corresponding modules of the first package. Such a connection entails comparable pressure conditions, ie transmembrane pressures, since the unfiltrate flow is generated by the same pump.

There are two further options for backwashing: one or more modules of a second module unit are backwashed with one or more modules of a first module unit. The pump of the first module unit is used for this purpose, or one or more modules of a second module unit are backwashed with filtrate from a filtrate buffer tank and a corresponding pump.

This makes it possible for the flow rate or volume flow through the membrane to be greatly increased during the backwash process (both with beer and with cleaning media). An increase in the volume flow by at least 2 to 10 times the volume flow during production is particularly advantageous. For example, with a production rate of 50 l/m ² h, this can be a backwash rate of 300 l/m ² h. Several modules can be backwashed at the same time. Any number of modules (1-n) to be backwashed can be selected. The backwash direction through the module can also be changed. It is therefore possible to change the speed and flow path, especially during backwashing. The backwash speed can also be selected differently depending on the individual module.

According to a preferred embodiment, the first and second line sections of the unfiltrate line are connected to one another, with the unfiltrate being able to be circulated through the unfiltrate line and the modules and/or the unfiltrate line of a first module package is connected to an unfiltrate line of a second module package, i.e. by switching the corresponding ones Valves can be connected.

According to a preferred embodiment, it is possible for the filter arrangement for n modules to have at least n−1 cleaning connections (eg CIP connections), in particular in the first common line section and the second common line section. A corresponding connection can then be arranged between the modules in each case. It is also possible to provide n or n+1 connections.

According to a preferred embodiment, each module has two separate cleaning connections (CIP connections) in order to direct a cleaning medium, for example via the headspace of the module, into the first or second unfiltrate connection of the module. This means that either a corresponding connection can be provided between two modules in the unfiltrate line, which can then be shared by two adjacent modules, or separate connections are provided. This means that the modules can be flushed in any direction from both the first and the second connection.

Although the above-mentioned connections are described in particular as cleaning connection(s) and in particular for CIP, of course they can also and/or alternatively be used for venting and/or for pushing out to the gully or the like.

The filtration method with a filter arrangement according to at least one of claims 1 to 9 is characterized in that the valve arrangements are switched in such a way that the individual modules are selectively flowed through with unfiltrate either from the first or second unfiltrate connection and/or are decoupled from the unfiltrate flow, i.e. that the unfiltrate stream does not flow through the corresponding modules. According to a preferred embodiment, it is possible that only the filtrate outlets of the decoupled modules are closed. The unfiltrate inlets remain open.

It is possible to switch the valve devices during the filtration and/or during the cleaning of the modules in such a way that the direction of flow of the unfiltrate or cleaning medium is reversed through a module of a module package and/or a module is operated in a clocked manner, clocked here meaning that the module is operated at intervals, i. H. for example, a bypass is temporarily switched.

It is also possible for the valve arrangement to be connected in such a way that filtrate from a first module is fed via the filtrate discharge line to the filtrate outlet of another module for backwashing and, in particular, if several module packages are provided, the unfiltrate from the nth module of the first package is routed via the common filtrate line is fed to the filtrate outlet of the nth module of the second module package for backwashing.

According to a preferred embodiment, the filtrate produced by the modules is fed to a filtrate buffer tank and, for example, during backwashing, at least one of the modules is flushed with filtrate from the buffer tank while other modules produce filtrate, i.e. are in filtration mode. This means that it is possible, for example, that filtrate a module pack or a module unit, which comprises a plurality of module packs, is fed to the filtrate buffer tank, and at least one module of another module pack or another module unit is backwashed with filtrate from the buffer tank.

The same enables continuous operation.

However, backwashing can also take place in such a way that, for example, several modular units are provided, each comprising several module packages, the first module unit having a collective filtrate discharge line via which the filtrate from several modules, in particular from all module packages, runs off.

The filtrate of this first module unit can be used for backwashing at least one module of a second module unit via the collective filtrate discharge line. Preferably, the number of backwashed modules of the second module unit is less than the number of modules that produced the filtrate. Backwashing at high pressure is therefore possible. It is also conceivable that a module is backwashed with filtrate that is currently being produced by other modules and at the same time filtrate is also supplied from the filtrate buffer tank in order to increase the backwash pressure.

It is advantageous if individual modules of a module package are backwashed or cleaned individually, so that the highest possible backwash pressure and/or cleaning pressure can be obtained. Since it is possible to clean or backwash the modules individually, each module can be cleaned according to its individual needs, i.e. depending on the operating time and/or the degree of contamination, for example.

However, the modules of a module pack can then be backwashed and/or cleaned one after the other in order to ensure that all modules of a module pack are in a cleaned state or in a state suitable for the next filtration.

In addition, the individual modules can be selectively backwashed from the lower and/or upper filtrate outlet. The module can have an upper and a lower filtrate outlet, both of which are connected to a filtrate space.

The filtrate used for cleaning, in particular backwashing, is, as described above, for example a product, in particular beer. However, it can also be backwashed with a CIP medium. A CIP medium can also not only be used for backwashing, but also flow through the modules through the unfiltrate lines in order to clean the modules in this direction, in the filtration direction.

If filtered product, in particular beer, is used as a medium for backwashing a module, the medium can, after backwashing, be returned to the unfiltrate line of a module package and/or, for example, via this path to a buffer tank for unfiltrate or concentrate, or alternatively be discarded via a cleaning connection. This means that the medium can either be discarded for backwashing or buffered and returned to filtration at a later point in time.

Fig. 1a

zeigt grob schematisch ein Ausführungsbeispiel einer Filtervorrichtung gemäß der vorliegenden Erfindung mit zwei Modulpaketen.

Fig. 1b

zeigt eine besondere Ausgestaltung des in Fig. 1a gezeigten Ausführungsbeispiels

Fig. 2

zeigt grob schematisch eine Filtervorrichtung gemäß der vorliegenden Erfindung mit zwei Moduleinheiten, die jeweils zwei Modulpakete mit mehreren Modulen aufweisen.

Fig. 3a

zeigt grob schematisch unterschiedliche mögliche Durchströmungsrichtungen durch die Module eines Modulpakets durch Schalten der Ventileinrichtungen

Fig. 3b

zeigt grob schematisch unterschiedliche Durchströmungsrichtungen durch Richtungsumkehr der Strömung durch das ganze Modulpaket

Fig. 4

zeigt grob schematisch das Rückspülen eines zweiten Filterpakets mit Filtrat eines ersten Filterpakets.

Fig. 5

zeigt grob schematisch das Rückspülen einer ersten Moduleinheit mit Filtrat von einer zweiten Moduleinheit.

Fig. 6

zeigt grob schematisch das Rückspülen einzelner Module einer ersten Moduleinheit durch Filtrat einer zweiten Moduleinheit.

Fig. 7

zeigt eine weitere Ausführungsform, bei der eine Moduleinheit mit Filtrat aus einem Puffertank rückgespült wird.

Fig. 8

zeigt grob schematisch einen Crossflow-Filter gemäß dem Stand der Technik.

Fig. 9

zeigt ein Modulpaket mit CIP Anschlüssen gemäß der Erfindung

According to a preferred exemplary embodiment of the present invention, the module from a module package is cleaned individually by backwashing depending on a filter parameter and/or the direction of flow of the unfiltrate is changed during operation. In doing so, e.g. B. the transmembrane pressure can be measured. When a first limit value is reached, for example, the direction of flow through the module can be changed, while backwashing takes place when a second limit value is reached. The advantage of the invention is that individual modules in a module package or a module unit can also be cleaned during operation by changing direction or can also be backwashed individually without the other modules being backwashed. Cleaned means the removal of the top layer or, to put it more precisely, a more even distribution of the top layer, which can extend the duration of the filtration. It is also possible that when a specific limit value is reached, the modules are decoupled by switching the valve devices or are operated in a clocked manner. The present invention is explained in more detail below with reference to the following figures:

Fig. 1a

shows a rough schematic of an embodiment of a filter device according to the present invention with two module packages.

Fig. 1b

shows a special design of the in Fig. 1a shown embodiment

2

shows a rough schematic of a filter device according to the present invention with two module units, each having two module packages with several modules.

Figure 3a

shows, roughly schematically, different possible directions of flow through the modules of a module package by switching the valve devices

Figure 3b

shows a rough schematic of different flow directions by reversing the direction of flow through the entire module package

4

shows a rough schematic of the backwashing of a second filter pack with filtrate from a first filter pack.

figure 5

shows a rough schematic of the backwashing of a first module unit with filtrate from a second module unit.

6

shows a rough schematic of the backwashing of individual modules of a first module unit using filtrate from a second module unit.

7

FIG. 12 shows a further embodiment in which a module unit is backwashed with filtrate from a buffer tank.

8

shows a roughly schematic crossflow filter according to the prior art.

9

shows a module package with CIP connections according to the invention

Fig. 1a shows a rough schematic of an embodiment of a filter device 1 according to the present invention with a module unit 4, consisting of two module packages 3a, 3b, each module package comprising three crossflow modules.

In this application, the expression "module" is understood to mean a crossflow module which, for example, comprises plastic hollow fibers (or ceramic filter cartridges with microfiltration pores of, for example, 0.45 μm). A module comprises, for example, a membrane cartridge with a large number of hollow fibers (e.g. 2,000 to 3,000) which are potted in the jacket tube of the cartridge. Potting can also be done directly into the pressure pipe. The module can, for example, be 0.5 to 1.5 m long, in particular 0.7 to 1 m. In principle, all common crossflow filter modules are suitable for the present invention, which for the filtration of beer have a pore size in a range from 0 .2 μm to 1.2 μm, in particular 0.3 μm to 0.7 μm. For example, a module may have two headspaces at opposite ends that communicate with unfiltrate ports of the module. A filtrate discharge to the outside can also be carried out through the respective head space. However, the filtrate discharge can also branch off to the side of the membrane cartridge. In particular, two filtrate discharges can also be provided.

A module package 3 comprises at least two, in particular at least three, modules 2.

A module unit 4 comprises at least two module packages 3 arranged next to one another. The module packages of a module unit have a common pump 15 for the unfiltrate. A respective modular unit 4 stands in particular on its own frame.

How out Fig. 1a shows, 2 module packages are provided here, module package 3a and module package 3b. The modules 2 each have a first unfiltrate connection 6, here on the top of the respective module and a second unfiltrate connection 7 on the opposite side, for example in the respective headspace of the module. The modules also have at least one filtrate outlet, in this case two filtrate outlets 8, which open into respective filtrate outlet lines 12 ₁ , 12 ₂ , 12 ₃ , with the filtrate outlets 8 of the modules 2 of the second module package 3b also running into the corresponding filtrate line 12 ₁ , 12 ₂ , 12 ₃ open, ie that the respective at least one filtrate outflow of the respective modules opens out into a respective filtrate outflow line 12, wherein if n modules are provided in a module package 3a, b, the nth filtrate outflow of an nth module of the first Module package 3a and the nth filtrate outlet 8 of a second module package 3b open into a common nth filtrate outlet _12n . Such a connection entails comparable pressure conditions, ie transmembrane pressures, since the unfiltrate flow is generated by the same pump 15 .

The individual filtrate discharge lines _12n can open into a common line 14, as shown in FIG Fig. 1a emerges. According to the present invention, the filter device 1 has a valve arrangement with a plurality of valve devices 11, i.e. valves or flaps, the valve arrangement being designed in such a way that the individual modules 2 can be flowed through with unfiltrate either from the first or the second unfiltrate connection 6, 7 .

It would also be possible to use two corresponding three-way valves for each module, with a corresponding three-way valve on each side of the module being connected to a non-filtrate line before and after the module and to the first or second non-filtrate connection.

How out Fig. 1a shows, in this exemplary embodiment, the module packages 3 are arranged parallel to one another and their respective first unfiltrate connection 6 is connected to a first common line section 10a of the unfiltrate line 10 . The respective second unfiltrate connection 7 is connected to a second common line section 10b of the unfiltrate line 10 . The first and second unfiltrate line 10a, 10b are connected to one another in such a way that unfiltrate can be circulated through the modules 2. In each case before and after the respective first and second unfiltrate connections, the valves 11 are then arranged, which can be switched in such a way that the respective module can be flowed through with unfiltrate either from the first or the second unfiltrate connection. The respective modules 2 also have cleaning connections 13 in the respective upper and lower head space, via which, for example, cleaning agent can be routed through the module instead of the unfiltrate via the unfiltrate connection 6 . A cleaning connection 13 is also provided at the lower end which, for example, the CIP medium derived via the second unfiltrate connection 7, for example discarded in the gully.

However, the cleaning connections 13 can also be provided for another purpose. The upper connection 13 can be used, for example, for venting, and the lower connection 13 can be provided, for example, for expelling unfiltrate or cleaning medium into a gully or tank. The connection(s) 13 can be present in each module 2 or can also be combined per module package 3 .

The valve devices 11 can be switched in such a way that the modules 2 ₁ , 2 ₂ , 2 ₃ can be operated in series and, in particular, the direction in which the unfiltrate can flow through the respective module can be set individually for each module.

A particular embodiment is characterized in that a respective membrane module such as 2, ( Fig. 1a ) via two unfiltrate inlets (one at the top via line section 10a with valve 11a and one at the bottom via line section 10b with valve 11b), two unfiltrate outlets (one at the top with a valve at 11c and one at the bottom with a valve at 11d) and two filtrate outlets (one at the top at 8a one below 8b). The outlets 11c and 11d of the module 2 ₁ (eg 2n-1) then become corresponding inlets for the following module 2 ₂ (eg 2 n).

During operation (filtration and/or cleaning), one non-filtrate inlet (11a or 11b), one non-filtrate outlet (11c or 11d) and one filtrate outlet (8a or 8b) are always open, and the other valves in the pairs are closed accordingly. Unfiltrate inlet and filtrate outlet are preferably open on the opposite side of the module, i.e. either 11a and 8b or 11b and 8a. It is also particularly advantageous if the filtrate outlet remains closed on the unfiltrate inlet side (i.e. according to 8a "closed" with 11a/8b open flow or 8b "closed" with 11b/8a open flow), so that an optimal, complete flow through the module and its membrane is achieved becomes. Equal opening of unfiltrate inlet and filtrate outlet leads to an uneven, incomplete membrane/membrane module flow and reduces not only the filtrate flow but also the service life of the membrane. The unfiltrate inlet and the unfiltrate outlet are advantageously on opposite sides of the module. When the direction is reversed, the positions of the open and closed valves are reversed, eg 11a/11d/8b "open" with 11b/11c/8a "closed". As a result, a flow reversal that can be implemented in a structurally particularly simple manner is achieved.

In the event of a complete flow reversal of the entire cossflow volume flow, the inflow and outflow directions can also change completely, so that the unfiltrate inlets 11a and/or 11b then become unfiltrate outlets and, conversely, 11c and/or 11d become the inlets.

This circuit is suitable both for production with beer and for cleaning. The same applies to the other membrane modules Fig. 1a : 2 ₂ , 2 ₃ .

The Figure 1a also shows a line 41, which represents the inflow from the buffer tank unfiltrate, and a line 42, which enables concentrated unfiltrate to flow back from the crossflow circuit to the buffer tank unfiltrate.

Figure 1b essentially corresponds to the Figure 1a , but further discloses a circuit for accomplishing flux reversal. In Figure 1b different opposite flow directions are possible as shown by the arrows.

The device has a switching device 43, 44, 46, 48 for reversing the direction of flow through the modules, as in FIG Fig. 1b represented by the directional paths with a different line. The bypass line 45 with the valves 43 (e.g. double seat valve) and 44 and the bypass line 47 with the valves 46 and 48 (e.g. double seat valve) around the crossflow pump 15 enable switching of the complete flow reversal in the crossflow circuit. In the event that the increase in concentrate up to the last membrane module in the series connection is particularly large, this enables the membrane to be evenly loaded by the flow reversal of the entire package.

In the event of a flow reversal, the unfiltrate outlet of a unfiltrate connection 7 becomes the unfiltrate inlet in the last module 2 ₃ (or 2n). Even if only in Figure 1b shown, this also applies to the other figures. The functionality is analogous to that in Figure 1a described.

Figure 3a shows the possible interconnection of, for example, a module package 3 with three modules 2, which is only possible through the particularly advantageous construction with the respective two unfiltrate inlets, two unfiltrate outlets and two filtrate outlets. By switching the valves 11, for example, as can be seen from the first column of the first line of the examples, the unfiltrate can enter the first module through the second unfiltrate connection 7 and leave the module at the first unfiltrate connection 6, ie at the top here. The flow then flows through the second module from top to bottom and the third from bottom to top. By switching the valves 11, as can be seen from column 2, line 1, the unfiltrate flow can be easily reversed here. However, the device according to the invention not only enables a reversal of the flow path as in Figure 3a is shown, but also a reversal of flow direction, that is, a flow like out Figure 3b can be done either from left to right, that is, from the first to the end module, but also in the reverse direction from right to left, that is, from the end to the first module.

By reversing the direction of flow in the individual modules, the pressure loss gradient when unfiltrate flows through is reversed over the length of the module. This also reverses the local transmembrane pressure over the length of the membrane. The effect of this is that the membrane is locally loaded with dirt to varying degrees. A large transmembrane pressure difference at the inlet causes a strong flux through the membrane, which forces dirt more into the pores of the membrane, which in turn makes cleaning the membrane more difficult. A small transmembrane pressure difference at the outlet of the membrane, in particular membrane hollow fibers, in turn causes less dirt to be transported to the membrane and less pollution. However, this also means a lower local flux through the membrane.

If the flow is now reversed in good time, the membrane can be loaded evenly with dirt. In addition, the parts of the membrane that are still clean can be fully utilized for filtration. Such as from Column 1, Line 2 of the Figure 3a shows, it is also possible to decouple at least one of the modules from the filtrate flow by switching the valves 11, ie to set a bypass, for example, or at least to close the valves in the filtrate discharge line of the respective module. This means that the filtrate no longer flows through the corresponding module. Here the last module is decoupled from the filtrate flow. Such a decoupled module can, for example, be backwashed in a targeted manner, or the modules can also be operated in a clocked manner, ie they are briefly decoupled from the filtrate stream and then, as in column 1, line 3 of Figure 3a is shown, are again applied and flowed through with unfiltrate. The Figure 3a shows the variety of ways in which the individual modules can be interconnected.

According to the method according to the invention, switching the flow direction or decoupling from the filtrate flow during production, ie during filtration, as described above, has the advantage that the membrane surface is uniformly loaded comes with dirt, whereby the clocked operation or the flow reversal also has a cleaning effect, ie cleaning of the membrane can take place, which leads to an overall increase in the service life of the filter.

However, the device according to the invention is not only advantageous for the current filtration operation; The valve arrangement is also extremely important for cleaning and backwashing the modules. There are basically two ways to do this, namely backwashing and cleaning:
During cleaning, cleaning medium is fed in the direction of filtration to the unfiltrate line 10 via one or more corresponding connections and then also filtered. In principle, it is also possible for the cleaning medium to be supplied via the connections 13 on the module for CIP cleaning. With this method, individual modules in particular can be cleaned in between and uncoupled for this purpose, as shown in Figure 3a emerges. However, it is also possible that cleaning medium can be routed through the series-connected modules 2 via only one CIP connection instead of the unfiltrate, with the direction also being variable here or individual modules being able to be operated in cycles. 9 shows a different arrangement of a cleaning connection here CIP connection. Here the CIP connection is provided in each case between two valves 11 between two modules 2 in the upper and lower line sections 10a, 10b. In this way, one CIP connection 13 can be used for the left-hand and right-hand neighboring module 2 in each case. After cleaning, the medium can then either be returned to the unfiltrate cycle, ie it can be fed into an unfiltrate line or into an unfiltrate buffer tank, or it can be discarded.

Cleaning in the direction of filtration can be carried out with the following cleaning media (e.g. CIP media): acid (possibly with additives), lye (possibly with additives), other additives, e.g. enzymes, water.

There is also cleaning against the direction of filtration, with cleaning media being fed backwards through the membrane via the connections 8 and leaving the module 2 via at least one non-filtrate connection. The same cleaning media mentioned above can be used for this.

The cleaning takes place after the actual filtration operation, i.e. after the last product, for example beer, has been filtered and pushed out of the filter.

Backwashing takes place during the actual filtration operation for individual modules or module packages. This means that you need a very clean cleaning medium, otherwise you will get dirt on the back. Even when backwashing the individual modules, they can be controlled individually and specifically by the valve devices 11 .

A very clean medium is required for backwashing. Backwashing can be done with the product, here beer or water or beer and water. In principle, it is advantageous to use the product, here the beer, for backwashing during production, with z. B. Advantageously, the filtrate produced in a module 2 can be used to backwash another module, which saves time (as e.g. in 4 is shown). Here, for example, filtrate from a first module 2 is fed to the filtrate outlet 8 of another module 2 via the filtrate outlet line 12 . If several n module packages are provided, here module package 3a and 3b, the unfiltrate, for example, the first module 2 ₁ can be fed to the filtrate outlet 8 of the first module 2, the second module package 3b via a common filtrate discharge line 12 ₁ for backwashing. How out 4 shows, the filtrate of the second module of pack 3a can be fed to the second module of pack 3b and the filtrate of the third module of pack 3a can be fed to the third module of pack 3b via the respective common filtrate lines. How out 4 shows, the backflushing medium can then be discharged via the individual cleaning connections or CIP connections 13 (lower connection 13 advantageously/upper connection 13 can be used for venting) and does not have to flow back into the unfiltrate circuit. The valves 11', which are arranged in the upper and lower unfiltrate line 10a, 10b before and after the first and last module, should then be closed during backwashing, since the module pack 3b is flushed and separated from the module pack 3a that produces must become.

This is just one example of a possible type of backwash. How out figure 5 shows, it is also possible, if there are two module units, each with several module packages 3, that the filtrate of a second module unit 4 ₂ is supplied via a collecting filtrate discharge line 14 to a first module unit 4 ₁ in order to backwash the modules. This means that one module unit can produce the backwash medium for another and can supply it via a valve node.

In order to increase the backwash quantity, for example, the number of backwashed modules can be smaller than the number of filtrate-producing modules of the second unit 4 ₂ . It is particularly advantageous if the modules are backwashed individually, e.g. B. Beginning with the module 6 in 6 and then the other modules are backwashed one after the other from module 6 to module 1.

According to the 7 shown embodiment, it can also be advantageous if the filtrate produced by the modules is collected in a filtrate buffer tank 16. This filtrate can then be used for backwashing. One or more modules up to n modules can be backwashed at the same time. Advantageously, only one module can also be backwashed in a targeted manner. There is a pump 17 at the outlet of the filtrate buffer tank. The individual modules can then be flushed one after the other from below and/or from above, so that there is no asymmetrical contamination.

According to a preferred exemplary embodiment of the present invention, no additional pump is required for backwashing via the filtrate buffer tank 16 . A pump, which is arranged in particular after the filtrate buffer tank, can be used both as a filtrate pump and as a backwash pump.

However, it can also be the case that, with a view to possible time savings, several, in particular all, modules are backwashed at the same time.

However, it is also possible that, with regard to asymmetric contamination of different modules, they are backwashed differently. The degree of contamination can be determined/calculated, for example, using the increase in transmembrane pressure. The backwash quantity and/or backwash flow can then be selected differently for the individual modules or for several modules. Asymmetrical contamination or degree of contamination can be understood as different contamination of individual modules and/or uneven contamination within a module.

In principle, in the previous exemplary embodiments, the backwashed medium can be discharged, for example, via at least one cleaning connection 13 of a corresponding module (preferably via the lower connection 13), and therefore does not have to be returned to the unfiltrate circuit.

This means that residues that have been rinsed off do not have to be passed through a subsequent module to remove the deposits. Since it is possible to clean or backwash the modules individually, each module can be cleaned according to its individual needs, i.e. depending on the length, intensity and degree of soiling. It would also be possible to discharge tailings in the bypass through the headspaces such that tailings do not have to be run through subsequent modules. For this purpose, the modules can be used, for example, as in Figure 3a Column 1 line 7 is shown to be interconnected.

By selectively switching the paths of the unfiltrate through the modules, it is possible to optimize the service life of the filter device, since the membrane in the modules is evenly soiled locally. This gives it a targeted, even coating inside and outside of the hollow-fiber membrane. An even covering is also easy to clean off. The targeted pulsing of individual modules is also advantageous during cleaning, since the membrane that is dirty is also cleaned and not just the one that allows the highest flow (which is usually the cleanest).

It is particularly advantageous if the device has control valves 40 or 40' or flow regulators, in particular in the filtrate discharge line, such that the flow (volume per time) or a value proportional thereto can be adjusted by a module, with the flow in particular of all modules in a module pack can be set to the same value, which enables uniform cleaning or backwashing and thus simultaneous backwashing or cleaning of all modules in a module pack.

The reversal of the flow direction or the initiation of a backwash process for one or more modules can take place depending on a filter parameter that can be measured individually for each module, for example the transmembrane pressure and/or the filtrate flow per time per module (i.e. volume flow per time per module). Module). It is also possible to initiate flow reversal or cycling or backwashing after a predetermined time has elapsed and/or a certain amount has been filtered. Alternatively, backwashing can also be initiated for an entire module package, not just for a single module.

When speaking of the inlet of a module, the term inlet of a module is also to be understood as a synonym.

Claims (21)

1. Filter device (1) with at least one module pack that comprises a plurality of modules, in particular three modules, for crossflow filtration, which have a first unfiltered material connection (6) at a first end of the module (2) and a second unfiltered material connection (7) on the opposite side of the module (2), as well as at least one filtrate outlet (8),
   characterised by
   a valve arrangement that is designed such that unfiltered material can optionally flow through the individual modules, either from the first or the second unfiltered material connection (6, 7).
2. Filter device (1) according to claim 1, characterised in that a plurality of modules (2) are arranged parallel to one another and their respective first unfiltered material connection (6) is connected to a first common conduit section (10a) of an unfiltered material conduit (10) and their respective second unfiltered material connection (7) is connected to a second common conduit section (10b) of an unfiltered material conduit (10), wherein arranged respectively before and after the respective first and second unfiltered material connections (6, 7) are valve devices (11) which can be switched such that unfiltered material can flow through the respective module (2) either from the first or the second unfiltered material connection (6, 7).
3. Filter device (1) according to claim 1 or 2, characterised in that the valve devices (11) of the valve arrangement can be switched such that the modules (2) can be operated in series, and in particular for each module (2) it is possible to set the direction in which the unfiltered material can flow through the respective module (2).
4. Filter device (1) according to at least one of the claims 1 to 3, characterised in that the valve devices (11) can be switched such that there can be a flow through a first module (2) in a first direction and there can be a flow through a subsequent module (2) in a second direction opposed to the first direction, and/or the valve devices (11) can be switched such that at least one module (2) is bypassed.
5. Filter device (1) according to at least one of the claims 1 to 4, characterised in that the filter device (1) comprises a plurality of module packs (3) which form a modular unit (4) and preferably comprises a plurality of modular units.
6. Filter device (1) according to at least one of the claims 1 to 5, characterised in that module packs (3) of a modular unit (4) have a common unfiltered material pump (15).
7. Filter device (1) according to at least one of the claims 1 to 6, characterised in that filtrate from the at least one filtrate outlet (8) of at least one module (2) can be conducted into the at least one filtrate outlet (8) of at least one other module (2) for backflushing, wherein in particular the respective at least one filtrate outlet (8) of the respective modules (2) opens into a respective filtrate outlet conduit (12), wherein if n modules (2) are provided in a module pack (3), the n^th filtrate outlet (8) of an n^th module (2) of a first module pack (3) and the n^th filtrate outlet (8) of a second module pack (3) open into a common n^th filtrate outlet (12).
8. Filter device (1) according to at least one of the claims 1 to 7, characterised in that the first and second conduit sections (10a, b) of the unfiltered material conduit (10) are connected to one another and the unfiltered material can be circulated through the unfiltered material conduit (10) and the modules (2), and/or
   the unfiltered material conduit (10) of a first module pack (3) is connected to an unfiltered material conduit of a second module pack (3).
9. Filter device (1) according to at least one of the claims 1 to 8, characterised in that in the filter device (1) for n modules (2) at least n-1 cleaning connections, in particular CIP [cleaning in place] connections (13), are provided, in particular in the first common conduit section and the second common conduit section, or
   each module (2) has two cleaning connections (13) of its own, in particular CIP connections, in order to conduct a cleaning agent, in particular a CIP medium, through the module (2) via the first or second unfiltered material connection, or for the unfiltered material or cleaning agent that can be supplied via the unfiltered material conduit (10) to the respective module (2) to be discarded via the lower cleaning connection (13), wherein the upper cleaning connection (13) can serve for venting.
10. Filtration method with a filter arrangement according to at least one of the claims 1 to 9, 19 or 20, characterised in that the valve devices (11) of the valve arrangement can be switched such that the individual modules (2) can optionally have unfiltered material flow through them respectively either from the first or the second unfiltered material connection (6, 7) and/or are disconnected from the unfiltered material flow.
11. Method according to claim 10, characterised in that during filtration and/or during cleaning of the modules (2), the valve devices (11) are switched such that the direction of flow through at least one module (2) of a module pack (3) is reversed and/or a module (2) is operated in a clocked manner.
12. Method according to claim 10 or 11, characterised in that the valve devices (11) are interconnected such that filtrate from a first module (2) is supplied via the filtrate outlet conduit (12) to the filtrate outlet (8) of a further module (2) for backflushing, and in particular
    if several module packs (3) are provided, the unfiltered material of the n^th module (2) of a first module pack (3) is supplied via a common filtrate discharge conduit (12) to the filtrate discharge outlet (8) of the n^th module (2) of a second module pack (3) for backflushing.
13. Method according to at least one of the preceding claims, characterised in that any filtrate that is produced is supplied to a filtrate buffer tank (16), and wherein respectively at least one of the modules (2) is backflushed with filtrate from the buffer tank (16) whilst other modules (2) produce filtrate and preferably the filtrate of a module pack (3) or a modular unit (4) that comprises several module packs is supplied to the filtrate buffer tank (16) and simultaneously at least one module (2) of another module pack (3) or another modular unit (4) is backflushed with filtrate from the buffer tank (16).
14. Method according to at least one of the preceding claims, characterised in that a plurality of modular units (4) is envisaged, which respectively comprise a plurality of module packs (3), wherein the first modular unit (4) has a collective filtrate discharge conduit (14), via which the filtrate from a plurality of modules (2) is discharged, in particular from all the module packs (3), wherein preferably
    the filtrate of this first modular unit (4) is used, via the collective filtrate discharge conduit, for backflushing at least one module (2) of a second modular unit (4), wherein in particular the number of backflushed modules (2) of the second modular unit (4) is smaller than the number of modules (2) that have produced the filtrate.
15. Method according to at least one of the claims 10-14, characterised in that the modules (2) of a module pack (3) are preferably backflushed individually, one after another, through an upper and/or lower filtrate outlet (8).
16. Method according to at least one of the claims 10 to 15, characterised in that the filtrate used for cleaning is either a product, in particular beer, or else a CIP medium.
17. Method according to claim 14, characterised in that when a filtered product, in particular beer, is used as a cleaning agent for backflushing a module, after the backflushing the product is returned to the unfiltered material conduit (10) of a module pack (3), and/or to a buffer tank for unfiltered material or concentrate, or optionally is discarded via a cleaning connection (13).
18. Method according to at least one of the claims 10 to 17, characterised in that a module (2) of a module pack (3) is cleaned individually, depending on a filter parameter, by backflushing, and/or during operation the direction of flow of the unfiltered material is changed, or the module is disconnected.
19. Filter device according to at least one of the claims 1-9, characterised in that the device has control valves (40, 40') or flow regulators, in particular in the filtrate discharge conduit (12), such that the flow through a module (2) can be adjusted, wherein in particular the flow through all modules (2) in a module pack (3) can be set to the same value, so that all modules of a module pack can be cleaned simultaneously.
20. Filter device according to at least one of the claims 1- 9 or 19, characterised in that the modules respectively have at least two filtrate outlets (8) spaced apart from one another, which in particular are arranged at opposite end areas of a corresponding module (2).
21. Filter device according to at least one of the preceding claims, characterised in that the at least three modules (3) can be interconnected such that unfiltered material can flow through them in series in a first direction of flow, and the direction of flow can be reversed by a switching device (43, 44, 46, 48) such that the at least three modules can have a flow through them in series in a second direction of flow that is opposed to the first direction of flow, wherein in particular an unfiltered material inlet of an unfiltered material connection (6,7) of a first module (2₁) becomes an unfiltered material outlet and the unfiltered material outlet of an unfiltered material connection (6,7) of a last module (2n) becomes an unfiltered material inlet, wherein the modules (2) can be flowed through preferably in circulation.

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